Alternative rear shock for GK76

[KiwiBiker]

Hi Guys, racing is finished for the season (I'm down under), so I have a chance to do some work on my GK76.
Despite putting .80Kg/mm racetech springs in the front forks my handling is still a bit loose when pushed hard and i think it's the rear shock.
I was going to get it rebuilt over the winter but a racer friend suggested i may be better off putting that money towards a more modern shock from a wrecker, one with compression and re-bound damping and a stiffer spring rate.

I found a tutorial on U tube of a guy fitting a GSXR600 K7 shock into his GK76.
https://www.youtube.com/watch?v=ZJAKou1B-qQ

I cant find a K7 shock for sale here but i can get an L10 or a L15 one that looks near new for good price.
Anyone know if these more modern model shocks are any different in size specs to the K7 variant?

I'm an engineering machinist so if a few mods are needed to make something fit then that's OK.

[moforockband]

I have a K6/7 gsxr600 shock in my 73a, and apart from going rusty it works great. Works great for track work, and not too shabby for the road either. Went in my 73 with no hassles, don't know about 76 though!

[KiwiBiker]

I have a K6/7 gsxr600 shock in my 73a, and apart from going rusty it works great. Works great for track work, and not too shabby for the road either. Went in my 73 with no hassles, don't know about 76 though!

Thanks mate, good to hear. I think i WILL JUST TAKE A GAMBLE AS i CAN GET A 2015 SHOCK THAT LOOKS BRAND new for NZD equivalent of 100 quid. If it turns out it doesn't fit I will on sell it.

Prob my only concern is with me being only 60kg the spring rate may be a bit stiff but I dont think it will be an issue in a track environment.
It feels like my rear end is moving around (that 'hinged in the middle' feeling) when I'm hard charging, not very confidence inspiring. Its a slow movement.
Feel free to offer any thoughts you may have on race set up that works for you on this bike. ie. Static and rider sags, comp & Rebound settings.

Cheers.

[moforockband]

I used to get on well when I raced my 73a BITD with the std shock. The 600/750 rear shock is an improvement, if you can get it to fit.
Just be warned that if you stiffen the front end, and run a longer shock you can run the risk of tankslappers, especially over rough tarmac. But on the track with smoother surface has not been a problem, and the bike puts in quicker lap times. Fitting a steering damper looks to me like sawing the fairing up, so still trying to suss that bit out.
HTH Nick.

[Nobbsie]

Hey kiwi i just brought a k6 750 rear shock, than ended up buying a ohlins 750 shock which i put in my bike,
so if your still looking for one let me know.
im up in ak so not much problem if you want it.
how did the season go?
i just rebuilt my front end too (re chrome and titanium coating with new pistons washers etc whole shebang
made a huge difference)

[KiwiBiker]

Hey Thanks mate. I'm guessing 750 and 600 shocks pretty similar eh? The dude at Bike busters has just got a GSXR 600 in so Im waiting on him to wreck it, but hey let me know your price and we will see eh.
Funny season down here with the Southland cup. They do two rounds before winter, break for three months, then do the other three rounds sept to Nov.
The first round was frustrating for me, I was faster than some of the back markers but didn't have the racing experience to get past them. I was placing myself at the back of the grid being the new boy. The May meeting I thought f**k it, put myself up the grid, wheel standed it off the line and got amongst it. Had some great duells with a couple of riders about my speed and ended up 3rd or 4th from the back. So happy with my progress at this stage. Just gotta be patient and do my apprenticeship.
Never gonna be able to compete with the souped up SV650's at the front anyways. Its all about grin factor at my level.
Your mods sound pretty impressive, good work.

[moforockband]

The little 400 will corner faster and get into the apex faster than an sv650 due to the frame geo. What usually holds the gsxr400 up is ground clearance.
What you need to get out of the 400 is mid range power to drive it out of the corner, and if you can learn to hold corner speed and learn the proper racing line, you will make a quantum leap in your results.
A cheap way to get mid range power is to use pod filters and a good 4 into 1, and jet it as close as you can to run from 6000 revs up.
Knowing what you want from your sussy is important. You want suspension that works, not really forks from a 1000 which will be over engineered for the bike. Fast response is more desireable than how big they are.
I like the std 73a sp RWU forks as I like the little bit bit of flex you get on hard use. It stops the tyre washing out.
Rebuilding your std forks, and springing them correctly (progressive springs are nice to learn on), and maybe a re-valve to suit the springs will make you more confident.
Maxton told me that by using lighter weight oils is more ideal, to keep the reactive speed of the forks up.
Hope some of that waffle helps lol!

[KiwiBiker]

The little 400 will corner faster and get into the apex faster than an sv650 due to the frame geo. What usually holds the gsxr400 up is ground clearance.
What you need to get out of the 400 is mid range power to drive it out of the corner, and if you can learn to hold corner speed and learn the proper racing line, you will make a quantum leap in your results.
A cheap way to get mid range power is to use pod filters and a good 4 into 1, and jet it as close as you can to run from 6000 revs up.
Knowing what you want from your sussy is important. You want suspension that works, not really forks from a 1000 which will be over engineered for the bike. Fast response is more desireable than how big they are.
I like the std 73a sp RWU forks as I like the little bit bit of flex you get on hard use. It stops the tyre washing out.
Rebuilding your std forks, and springing them correctly (progressive springs are nice to learn on), and maybe a re-valve to suit the springs will make you more confident.
Maxton told me that by using lighter weight oils is more ideal, to keep the reactive speed of the forks up.
Hope some of that waffle helps lol!

That's good waffle mate! thanks for the tips. Yeah I wasn't interested in chucking too much money at the bike so I'm sticking with the original forks and have put Racetech springs in with 5W oil to keep the action fast. Hard to fully appreciate my gains at this stage as the rear still needs attention. So once I get that sorted I can get it set up right and start working on my lean angles as I still haven't found the limit of my ground clearance yet.
My corner speed doesn't seem to be too bad (particularly entry speed) as this is where I often find myself being held up by guys on bigger bikes and it drives me nuts. I hate having to over brake and wash off speed because of these point and twist jockeys! Ive been riding CBR250 & 300's on the road for the last three years and a lot of my riding buddies have 1000cc bikes etc so I'm used to maximising my corner speed to make up lost ground on the straight bits. Great fun.

[Nobbsie]

Hey man just looked up my receipt it is a gsxr 600 k6 rear shock i payed 180 from bike busters (still have recept) let me know if you want it and make me a offer.
Cheers

[KiwiBiker]

Hey man just looked up my receipt it is a gsxr 600 k6 rear shock i payed 180 from bike busters (still have recept) let me know if you want it and make me a offer.
Cheers

Thanks, I dont trust wreckers fully so can you just check for me that it has a fork on the bottom with an opening of around 29mm and that the male piece on the top is about 26mm across the flats (ish).
If it looks like its going to fit how does $100 sound and I pay for postage?